The present invention relates to a surrounding frame which can be attached to a tower slewing crane and via which the tower slewing crane can be connected to an object such as a building.
The invention furthermore relates to a method of assembling the surrounding frame at a tower slewing crane, and to a use of the surrounding frame for connecting a tower slewing crane to an object.
When using tower slewing cranes, it is frequently necessary, particularly with high hook heights, to anchor the crane tower to an object such as to a building and thus to stabilize the crane tower in a particularly economic manner. The crane tower is typically surrounded by a so-called surrounding frame for this purpose which is connected to the crane tower without play and which can thus absorb the forces acting horizontally on the crane by direct contact. Anchorage braces which in turn connect the surrounding frame to the object and are anchored therein conduct the forces from the crane tower ultimately into the object.
As a rule in this respect, the surrounding frame comprises a U-shaped element which comprises a center section and two end sections and which surrounds the crane tower, which has a quadrangular cross-section, from three sides. The surrounding frame furthermore comprises a latching element which is supported in an articulated manner at the U-shaped element and which surrounds the crane tower at a fourth side in a closed position.
The center section of the U-shaped element of the surrounding frame is frequently facing the object to which the tower slewing crane is to be connected so that the anchorage braces connected to the object can be fixed in the region of the center section of the U-shaped element.
A surrounding frame designed in this manner admittedly satisfies the demands with respect to the stabilization of the tower slewing crane which is achieved by the connection of the crane tower to an object, but problems arise on the assembly of the surrounding frame at the tower slewing crane.
A crane which holds the surrounding frame at a suspension point and conveys it into an assembly position is used for assembling the surrounding frame for obvious reasons. In this respect, the surrounding frame hangs perpendicular in the air in a transport position during the transport from a storage position which is located in the proximity of the crane, but remote from the assembly position, to an assembly position which is located at a specific height of the crane tower. Since, however, the assembly position requires a horizontal position of the surrounding frame, it is necessary to rotate the surrounding frame from the transport position by 90° into the assembly position and to position the surrounding frame in the now horizontal assembly position such that the crane tower is located within the U-shaped element. Instead of a transport position perpendicular in the air, the surrounding frame can also already be held in a horizontal position on the transport to the assembly position. It is fastened to at least three points of the frame for this purpose. In this case, the suspension is admittedly more complicated to effect, but in turn, however, the rotation by 90° from the transport position into the assembly position is omitted.
It must be ensured in this respect that the two end sections of the U-shaped element do not collide with the structure of the crane tower. For this purpose, additional securing means such as chains or ropes are typically provided which are fixed to the tower construction and which are suitable for taking up the weight of the surrounding frame and for its positioning.